The present invention relates to a plastic container. More particularly this invention concerns such a container, crate, or box used for storage and transport.
A standard container used for storing and shipping freight is formed of molded plastic with a rectangular floor panel from whose edges side walls extend upward. A plurality of ribs extend downward from a lower face of the floor panel adjacent the edge and a floor strip parallel to the floor panel is fixed to the ribs and forms therewith an annular array of pockets having horizontally open mouths. Such a container, as described in German patent documents 3,909,022 of K. Korte and 4,338,063 is relatively robust. The flat floor strip ensures good surface contact with any supporting surface, making it particularly easy to handle this type of container with a roller conveyor.
The open box-like pockets formed between the floor panel and the underlying floor strip impart considerable rigidity and strength to the container. They are produced during manufacture of the container in a movable-part mold. In use, however, they tend to trap foreign matter, both solid and liquid. This makes the containers problematic when used with, for instance, foodstuffs as it is difficult or impossible to clean them thoroughly.
It is therefore an object of the present invention to provide an improved container.
Another object is the provision of such an improved molded plastic container which overcomes the above-given disadvantages, that is which is very rigid but easy to maintain clean.
A container has according to the invention a polygonal and generally planar upper or main floor panel having a plurality of edges, an upper face, and a lower face. Respective side walls extend upward from the edges of the floor panel and a plurality of ribs extend downward from the lower face of the floor panel adjacent the edge. An annular floor strip fixed to the ribs below the main floor panel forms with the main floor panel and the ribs an annular array of pockets having horizontally outwardly open mouths. In accordance with the invention, closure strips engaged over the mouths horizontally close the pockets and are fixed permanently to the mouths of the pockets.
Thus the structural advantages of these pockets, that is the rigidity, are retained, but the disadvantage, that is the dirt trapping, is eliminated. The containers according to the invention therefore have all the advantages of the prior art but none of the disadvantages. What is more, closing the outer ends of the pockets, whose inner ends are closed by an annular inner rib, greatly increases the rigidity of the floor panel, making the container according to the invention much stronger than the prior-art containers and capable of carrying substantially greater loads. Crushing of the floor panel and floor strip together is virtually impossible.
The floor panel, side walls, ribs, and floor strip according to the invention are unitarily formed of plastic. Furthermore the closure strips are unitarily formed of plastic with the floor panel, side walls, ribs, and floor strip and are joined to the floor strip by a unitary hinge so they can pivot between a closed position engaged over the respective mouths and closing same and an open position. The container is molded with the closure strips in the open position and, after separation from the mold, the closure strips are pivoted into the closed position where they are permanently fixed.
In accordance with the invention, strips are provided with barbed fasteners engageable in the pockets to hold them in place. Alternately welds between the closure strips and the mouths of the pockets secure them together. The mouths have planar rims that fit flush with the closure strips and where the welds are formed. These rims can be formed according to the invention with weld-holding grooves.
To facilitate sliding of the containers, either on a roller conveyor or up onto the tines of a fork lift, the closure strips and the floor strips meet at an outer edge that is rounded or beveled. Similarly the ribs can include an annular inner rib inwardly closing the pockets and meeting the floor strips at an inner edge that is beveled or rounded.
According to another feature of the invention, a central lower floor panel spaced below the upper or main floor panel within the floor strip has an outer edge joined to and unitary with the floor strip. This lower floor panel can have an upwardly recessed central portion. There is a normally vertical central rib fixed to the upper floor panel and to the lower floor panel.
The upper floor panel and lower floor panel are formed with vertically throughgoing drain holes. These are provided in the ribs so that any liquid trapped in the container will drain right through the floor panel and out.
A bridge strip parallel to the floor strip and supported by the ribs extends across an inner periphery of the floor strip spaced below the upper floor panel. This bridge strip forms with the respective ribs a horizontal passage and the container is formed in the passage with a blocking partition. The bridge strip is offset from the floor strip toward the floor panel.